2025年暑假乐园海南出版社七年级数学华师大版第16页答案
1. 已知$x,y$满足方程组$\left\{\begin{array}{l} x+6y=12,\\ 3x-2y=8,\end{array}\right. $则$x+y$的值为( ).
A. 9
B. 7
C. 5
D. 3

答案

C
2. 已知$\left\{\begin{array}{l} x=1,\\ y=2\end{array}\right. $和$\left\{\begin{array}{l} x=2,\\ y=c\end{array}\right. $都是方程$ax+by=0(b≠0)$的解,则$c$的值为( ).
A. 1
B. 2
C. 3
D. 4

答案

D
3. 方程$2x-y=3$和方程$y=x-2$的公共解是( ).
A. $\left\{\begin{array}{l} x=1,\\ y=-1\end{array}\right. $
B. $\left\{\begin{array}{l} x=-1,\\ y=1\end{array}\right. $
C. $\left\{\begin{array}{l} x=5,\\ y=3\end{array}\right. $
D. $\left\{\begin{array}{l} x=3,\\ y=1\end{array}\right. $

答案

A
4. 小刚解出了方程组$\left\{\begin{array}{l} 3x-y=3,\\ 2x+y=▲\end{array}\right. $的解为$\left\{\begin{array}{l} x=4,\\ y=■\end{array}\right. $.因不小心滴上了两滴墨水,刚好盖住了方程组和解中的两个数,则▲、■分别为( ).
A. 17,9
B. 16,8
C. 23,15
D. 15,23

答案

A
1. 方程组$\left\{\begin{array}{l} 2x+y=5,\\ 3x-y=10\end{array}\right. $的解是________.

答案

$\begin{cases}x = 3\\y = -1\end{cases}$
2. 请写出二元一次方程$3x+y=18$的一组正整数解:________.

答案

$\begin{cases}x = 1\\y = 15\end{cases}$（答案不唯一）
3. 已知$\left\{\begin{array}{l} x=3,\\ y=-1\end{array}\right. $是方程组$\left\{\begin{array}{l} 4x+my=9,\\ mx-ny=11\end{array}\right. $的解,那么$m=$________,$n=$________.

答案

$3$；$2$
4. 请写出一个解为$\left\{\begin{array}{l} x=3,\\ y=1\end{array}\right. $的二元一次方程组:________.

答案

$\begin{cases}x + y = 4\\x - y = 2\end{cases}$（答案不唯一）
5. 已知$x+y=4$,且$x-y=10$,则$2xy=$________.

答案

$-42$
6. 已知$|x+5y-6|+(3x-6y-4)^{2}=0$,则$(x+y)^{2}=$________.

答案

$\frac{100}{9}$